Monkey See, Monkey Do

Researchers: In tests, a monkey can feed itself by directing a robotic arm using its brain.

By Julie Steenhuysen
CHICAGO (Reuters) - Using only its brainpower, a monkey can direct a
robotic arm to pluck a marshmallow from a skewer and stuff it into its
mouth, researchers said on Wednesday.

"They are using a motorized prosthetic arm to reach out, grab and
bring the food back to their face," said Andrew Schwartz of the
University of Pittsburgh School of Medicine, whose study will appear in
an upcoming issue of the journal Nature.

Schwartz said the technology behind this feat may lead to
brain-powered prosthetic limbs for people with spinal cord injuries or
disabling diseases that make such simple tasks impossible.
Until now, such brain-machine interfaces have been used to control
cursor movements on a computer screen. Schwartz and colleagues wanted
to apply the technology to real-world tasks.
The monkey guides the robot arm the same way it does its natural limbs, through brain signals.

Schwartz' team picks up those signals through an array of
microelectrodes half the size of a thumbtack that has been implanted in
the monkey's brain. These signals are amplified and relayed to a
computer that operates the robotic arm.
Schwartz said his team has learned that certain motor neurons fire
rapidly when the monkey wants to move a certain way. "What is important
is each neuron seems to have a preferred direction," Schwartz said in a
telephone interview.
"One cell will fire a lot if you move upward. Another cell will fire
a lot if you move to the right. All you really need to do is listen to
these neurons at the same time to determine which direction the animal
wants to move in," he said.